1. Field of the Invention
This invention relates to a marker which is used for the confirmation of the paper web-threaded paths and a paper web-threaded path confirming apparatus for rotary presses.
2. Description of the Prior Art
A rotary press, for example, a newspaper press, is generally operated so that a plurality of paper webs are sent to the same folder unit through paper web threading paths via different feeders and different press units. In order that the paper webs are cut at the folder unit with the printed images positioned properly on the paper webs according to various conditions including the number of pages of the final newspaper, the presence or absence of images to be colorprinted and the order of laminating the printed paper webs, it is necessary that the paper webs from the feeders be sent from the press units to the folder unit through predetermined paper web threading paths the lengths of which are set properly in the space between the press units and folder unit.
According to the conventional techniques of this kind, confirming that the paper webs fed have been threaded through correct paths is done by only examining whether or not the newspaper discharged from the folder unit is cut with the printed images on each page thereof positioned properly.
The confirming of the paths, through which the paper webs have been threaded, according to the conventional techniques cannot be done unless the paper webs are printed by the printer. For example, in an offset press, in which the printing of paper webs is not done during a paper web threading operation due to various restrictions including the restrictions on an operation of the offset press, the confirming of the paper web-threaded paths cannot be done before a production printing operation has been completed. If paper webs should be threaded through a wrong path, a lot of wrong-printed paper webs are wasted, and, moreover, a good deal of time is spent in carrying a paper web rethreading operation and a correction operation for suitably matching the paper web cutting position with the printed images thereon by changing the positions of the adjust rollers. This causes the printing operation to delayed greatly.